export const getFooterTop = () => document.querySelector('footer').getBoundingClientRect().top
export const getHeaderBottom = () => document.querySelector('header').getBoundingClientRect().bottom
// export const getItemIndex = el => el ? el.className.match(/item-(\d+)/)[1] - 1 : -1
export const getItemMargin = () => parseFloat(getComputedStyle(document.querySelector('.item')).marginTop)